How to: Create Self-Joins Automatically (Visual Database Tools)
If a table has a reflexive relationship in the database, you can join it to itself automatically.
To create a self-join automatically
Add to the Diagram pane the table you want to work with.
Add the same table again, so that the Diagram pane shows the same table twice within the Diagram pane.
The Query and View Designer assigns an alias to the second instance by adding a sequential number to the table name. In addition, the Query and View Designer creates a join line between the two rectangles representing the two different ways the table participates in the query.